scholarly journals Microstructure and Corrosion Behavior of (CoCrFeNi)95Nb5 High-Entropy Alloy Coating Fabricated by Plasma Spraying

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 694 ◽  
Author(s):  
Wenrui Wang ◽  
Wu Qi ◽  
Lu Xie ◽  
Xiao Yang ◽  
Jiangtao Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Steel Substrate ◽  
Alloy Coating ◽  
High Entropy Alloy ◽  
Pitting Potential ◽  
Q235 Steel ◽  
High Entropy ◽  
Passivation Film ◽  
Elemental Segregation

In this paper, the (CoCrFeNi)95Nb5 high-entropy alloy (HEA) coating with a thickness of 500 μm on Q235 steel substrate was fabricated by plasma spraying. The microscopic results showed that a new Laves phase is formed in the (CoCrFeNi)95Nb5 HEA coating compared to the HEA powder, and elemental segregation occurs between the dendrites and the interdendrites of the coating, while the interdendritic phase enriches with the Cr and Nb. The phase composition change and elemental segregation behavior were mainly due to the faster cooling rate of the plasma spraying technique. At the junction of the coating and the substrate, the HEA coating bonded well to the substrate; in addition, the width of transition zone was merely 2 μm. The microhardness of the (CoCrFeNi)95Nb5 HEA coating was 321 HV0.5, which is significantly higher than that of the substrate. In terms of corrosion resistance, the (CoCrFeNi)95Nb5 HEA coating has good corrosion resistance in NaCl solution. Although the corrosion form was pitting corrosion, the pitting potential of the (CoCrFeNi)95Nb5 HEA coating was significantly higher than that of other coatings, which was mainly because of the dense passivation film formed by Cr and Nb on the surface of the coating. Once the passivation film was destroyed by Cl−, the selective corrosion occurred on the surface of the (CoCrFeNi)95Nb5 HEA coating. In summary, the (CoCrFeNi)95Nb5 HEA coating prepared by plasma spraying technology can significantly improve the corrosion resistance and mechanical properties of the Q235 steel substrate.

scholarly journals Fabrication of AlCoCrFeNi High-Entropy Alloy Coating on an AISI 304 Substrate via a CoFe2Ni Intermediate Layer

Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 2 ◽  
Author(s):  
Wenyuan Cui ◽  
Sreekar Karnati ◽  
Xinchang Zhang ◽  
Elizabeth Burns ◽  
Frank Liou
Keyword(s):  
Intermediate Layer ◽  
Steel Substrate ◽  
Alloy Coating ◽  
304 Stainless Steel ◽  
High Entropy Alloy ◽  
Intermediate Step ◽  
Dendritic Microstructure ◽  
Aisi 304 ◽  
High Entropy ◽  
Average Hardness

Through laser metal deposition, attempts were made to coat AlCoCrFeNi, a high-entropy alloy (HEA), on an AISI 304 stainless steel substrate to integrate their properties. However, the direct coating of the AlCoCrFeNi HEA on the AISI 304 substrate was found to be unviable due to cracks at the interface between these two materials. The difference in compositional change was suspected to be the source of the cracks. Therefore, a new transition route was performed by coating an intermediate layer of CoFe2Ni on the AISI 304 substrate. Investigations into the microstructure, phase composition, elemental composition and Vickers hardness were carried out in this study. Consistent metallurgical bonding was observed along both of the interfaces. It was found that the AlCoCrFeNi alloy solidified into a dendritic microstructure. The X-ray diffraction pattern revealed a transition of the crystal structure of the AISI 304 substrate to the AlCoCrFeNi HEA. An intermediate step in hardness was observed between the AISI 304 substrate and the AlCoCrFeNi HEA. The AlCoCrFeNi alloy fabricated was found to have an average hardness of 418 HV, while the CoFe2Ni intermediate layer had an average hardness of 275 HV.

scholarly journals Wear and Corrosion Resistance of Al0.5CoCrCuFeNi High-Entropy Alloy Coating Deposited on AZ91D Magnesium Alloy by Laser Cladding

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 915 ◽  
Author(s):  
Kaijin Huang ◽  
Lin Chen ◽  
Xin Lin ◽  
Haisong Huang ◽  
Shihao Tang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Alloy Coating ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Az91d Magnesium Alloy ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

In order to improve the wear and corrosion resistance of an AZ91D magnesium alloy substrate, an Al0.5CoCrCuFeNi high-entropy alloy coating was successfully prepared on an AZ91D magnesium alloy surface by laser cladding using mixed elemental powders. Optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction were used to characterize the microstructure of the coating. The wear resistance and corrosion resistance of the coating were evaluated by dry sliding wear and potentiodynamic polarization curve test methods, respectively. The results show that the coating was composed of a simple FCC solid solution phase with a microhardness about 3.7 times higher than that of the AZ91D matrix and even higher than that of the same high-entropy alloy prepared by an arc melting method. The coating had better wear resistance than the AZ91D matrix, and the wear rate was about 2.5 times lower than that of the AZ91D matrix. Moreover, the main wear mechanisms of the coating and the AZ91D matrix were different. The former was abrasive wear and the latter was adhesive wear. The corrosion resistance of the coating was also better than that of the AZ91D matrix because the corrosion potential of the former was more positive and the corrosion current was smaller.

Microstructure and wear behavior of FeCoNiCrMn high entropy alloy coating deposited by plasma spraying

2020 ◽  
Vol 385 ◽  
pp. 125430 ◽  
Author(s):  
Jin-Kun Xiao ◽  
Hong Tan ◽  
Yu-Qing Wu ◽  
Juan Chen ◽  
Chao Zhang
Keyword(s):  
Plasma Spraying ◽  
Wear Behavior ◽  
Alloy Coating ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals Frictional Wear and Corrosion Behavior of AlCoCrFeNi High-Entropy Alloy Coatings Synthesized by Atmospheric Plasma Spraying

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 740
Author(s):  
Yongkun Mu ◽  
Liangbo Zhang ◽  
Long Xu ◽  
Kondagokuldoss Prashanth ◽  
Nizhen Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Corrosion Behavior ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Frictional Wear ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

High-entropy alloy coatings (HEAC) exhibit good frictional wear and corrosion resistances, which are of importance for structure materials. In this study, the microstructure, surface morphology, hardness, frictional wear and corrosion resistance of an AlCoCrFeNi high-entropy alloy coating synthesized by atmospheric plasma spraying (APS) were investigated. The frictional wear and corrosion resistance of the coating are simultaneously improved with an increase of the power of APS. The influence of the APS process on the microstructure and mechanical behavior is elucidated. The mechanisms of frictional wear and corrosion behavior of the AlCoCrFeNi HEAC are discussed in detail.

scholarly journals Mechanically Alloyed CoCrFeNiMo0.85 High-Entropy Alloy for Corrosion Resistance Coatings

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3802
Author(s):  
Laura Elena Geambazu ◽  
Cosmin Mihai Cotruţ ◽  
Florin Miculescu ◽  
Ioana Csaki
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steel Substrate ◽  
Bulk Material ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Resistance Testing ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Entropy

High-entropy alloys could provide a solution for corrosion resistance due to their impressive properties. Solid-state processing of high purity Co, Cr, Fe, Ni and Mo metallic powders and consolidation resulted in a bulk material that was further machined into electro spark deposition electrodes. After the stainless steel substrate surface preparation, thin successive layers of the high-entropy alloy were deposited and Pull-Off testing was performed on the newly obtained coating, for a better understanding of the adhesion efficiency of this technique. Good adhesion of the coating to the substrate was proved by the test and no cracks or exfoliations were present. Corrosion resistance testing was performed in a liquid solution of 3.5 wt.% NaCl for 6 hours at room temperature and the results obtained validated our hypothesis that CoCrFeNiMo0.85 high-entropy alloys could provide corrosion resistance when coating a stainless steel substrate.

scholarly journals Microstructure and Mechanical Properties Investigation of the CoCrFeNiNbx High Entropy Alloy Coatings

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 409 ◽  
Author(s):  
Hui Jiang ◽  
Kaiming Han ◽  
Dayan Li ◽  
Zhiqiang Cao
Keyword(s):  
Wear Resistance ◽  
Steel Substrate ◽  
Alloy Coating ◽  
304 Stainless Steel ◽  
Molar Ratio ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
Face Centered Cubic ◽  
Laves Phases ◽  
High Entropy

In this work, the CoCrFeNiNbx (x: molar ratio, x = 0.45, 0.5, 0.75, and 1.0) high entropy alloy coatings were synthesized on a 304 stainless steel substrate by laser cladding to investigate the effect of Nb element on their microstructure, hardness, and wear resistance. The results indicated that in all of the CoCrFeNiNbx alloy coatings, two phases were found: One was a face-centered cubic (FCC) solid solution phase, the other was a Co1.92Nb1.08-type Laves phase. The microstructures of samples varied from hypoeutectic structure (x = 0.45 and 0.5) to hypereutectic structure (x = 0.75 and 1.0). The Vickers hardness of CoCrFeNiNbx alloy coatings was obviously improved compared with the substrate. The hardness value of the CoCrFeNiNb1.0 alloy coating reached to 590 HV, which was 2.8 times higher than that of the substrate. There was also a corresponding variation in wear properties with hardness evolutions. Wherein the hypereutectic CoCrFeNiNb1.0 alloy coating with the highest hardness exhibited the best wear resistance under the same wear condition, the dry wear test showed the wear mass loss of CoCrFeNiNb1.0 alloy coating was less than a third of the substrate. The high hardness and wear resistance properties were considered with the fine lamellar eutectic structure and proper combination of FCC and Laves phases.

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